[CupcakeDolly]

I know nothing of the series, but like Serra said before, it's a bias that's seen everywhere. Lesbian relationships aren't often taken seriously - I've experienced it myself, having people tell me that having sex with, or even being IN LOVE WITH, a girl "doesn't count." Unless it affects someone directly (like a guy getting dumped by the girl of his dreams because she's run off with another woman or something equally dramatic and in-your-face) people tend to downplay the importance of female relationships. Personally, I believe it's subconscious sexism. No matter what one claims to believe regarding gender equality, the past and the examples set by society are too firmly ingrained in people's minds.

There may be another aspect to it, though, based completely on your description of the characters and the events. It sounds as if this omnisexual man is being more 'promiscuous' toward other men which, let's face it, tends to be how most gay men in media are portrayed. Promiscuity being one of the main arguments against homosexuality (and probably the fact that he's a man too, those dirty sexists!) the writers/producers/creators, what have you, may have found the behavior a little icky. On the other hand, you have the typical concept of love transcending time and lasting on - probably more of a well-received romantic notion.